Please post dmesg output after changes are committed to emmc (with "w"). I had exactly the same issue - dmesg was reporting a lot of serious write errors. I already assumed that emmc is not usable anymore, however, after couple of weeks... I tried again and everything was OK. I am not sure if this was really hardware issue or software.
So, please check dmesg output...

Could you please point out how to achieve this? All my H3 (also H2+) devices suffer from the issue as described. Even with newest kernel. So, after reading I decided to test stability with "constant cpu frequency".
EDIT: I've done it by:
[root@PKTEST ~]# cat /etc/default/cpufrequtils
# WARNING: this file will be replaced on board support package (linux-root-...) upgrade
ENABLE=true
MIN_SPEED=408000
MAX_SPEED=1296000
#GOVERNOR=ondemand
GOVERNOR=performance
[root@PKTEST ~]#
Question: would it be possible not to overwrite cpufrequtils file once support package is installed/upgraded?